Portal de Periódicos da CAPES

Synthesis and structure of titanium tetrathiolate and tantalum pentathiolate complexes. Metal-sulfur bonding in early transition metal compounds

1995; Elsevier BV; Volume: 229; Issue: 1-2 Linguagem: Inglês

10.1016/0020-1693(94)04263-u

1873-3255

Douglas T. Corwin, James F. Corning, Stephen A. Koch, Michelle Millar,

Organometallic Complex Synthesis and Catalysis

The reaction of TiCl4 with potassium 2,3,5,6-tetramethylbenzenethiolate (KS-2,3,5,6-Me4C6H) in THF gives [Ti(S-2,3,5,6-Me4C6H)4] (1) in 50% yield. Compound 1 crystallizes in the triclinic space group P1 with a = 11.666(4), b = 19.417(5), c = 8.916(7)Å, α = 97.09(2), β = 110.30(2), γ = 87.95(3)°, V =1880(3), Å3, Z = 2. The monomeric [Ti(S-2,3,5,6-Me4C6H)4] has a distorted tetrahedral structure with TiS bonds of 2.292(6) Å. One of the thiolate groups has a very acute MSC angle of 86.5(5)°. The reaction of TaCl5 with excess (LiS-2,3,5,6-Me4C6H) in hexane gives [Ta(S-2,3,5,6-Me4C6H)5] (2). Compound 2 crystallizes in the triclinic space group, P1 with a = 11.165(9), b = 18.675(11) Å, α = 90.87(4), β = 101.83(6), γ = 96.77(5)°, V = 2407(5) Å3 with Z = 2. [Ta(S-2,3,5,6-Me4C6H)5) is a monomeric compound with a distorted five-coordinate geometry. The average TaS bond distance is 2.37(3) Å and TaSCav angle is 116(7)°. Structural comparisons of 1 and 2 with analogous phenolate complexes reveal large values for Δ[(MS)−(MO)]. The extent of the S to M gp-bonding in these electron deficient early transition metal thiolates is considerably reduced compared to the O to M π-bonding in phenolate analogs. The observation of the acute TiSC angles suggests that the limited thiolate metal π-bonding in 1 can not compensate for the strong electron deficiency of the Ti(IV) center.